Guido John A, Werner Sherry L, Meister Keith
Texas Metroplex Institute for Sports Performance, Grand Prairie, Texas 75050, USA.
J Strength Cond Res. 2009 Sep;23(6):1873-6. doi: 10.1519/JSC.0b013e3181b42535.
Ground reaction forces are important in pitching given that the only external contact a pitcher has is between the foot and the ground. Windmill softball pitchers are routinely seen clinically for injuries to the lower extremities, and lower-extremity kinetics have not been well studied. The purpose of this study was to investigate the relationships between ground reaction forces and throwing mechanics in youth windmill pitchers and to provide a scientific basis for the improvement of preventive and rehabilitative protocols. Fifty-three youth softball pitchers were tested in an indoor facility. High-speed video and force plate data were collected for fastballs from each pitcher. Average ball speed was 25 m/sec. Peak vertical ground reaction force averaged 139 % body weight (BW), peak anterior force averaged 24 %BW, and the medially directed component of the ground reaction force averaged 42 %BW. Loading rates to peak force in all 3 directions were high. Preventive and rehabilitative protocols for windmill softball pitchers can begin to be improved on the basis of knowledge of the magnitudes and times to peak forces under the stride foot.
鉴于投手与外界的唯一接触是脚与地面之间的接触，地面反作用力在投球过程中很重要。临床上经常见到风车式垒球投手下肢受伤，而下肢动力学尚未得到充分研究。本研究的目的是调查青少年风车式投手中地面反作用力与投掷力学之间的关系，并为改进预防和康复方案提供科学依据。53名青少年垒球投手在室内设施中接受了测试。收集了每位投手投出快球时的高速视频和测力板数据。平均球速为25米/秒。垂直地面反作用力峰值平均为体重（BW）的139%，前向力峰值平均为24%BW，地面反作用力的内侧分量平均为42%BW。在所有三个方向上达到峰值力的加载速率都很高。基于对跨步脚下达到峰值力的大小和时间的了解，可以开始改进风车式垒球投手的预防和康复方案。
